Atopy is a predisposition toward developing certain allergic hypersensitivity reactions. Atopy may have a hereditary component, although contact with the allergen or irritant must occur before the hypersensitivity reaction can develop.
As of 2012, 63.9 percent of players playing in Major League Baseball are white. There is no way of telling the exact number due to the number of players.
In Major League Baseball (MLB), it is calculated by dividing a player's hits by his at bats (AB). In MLB, a player in each league wins the batting title each season for having the highest batting average that year. Under current rules, a player must have 3.1 plate appearances (PA) per team game (for a total of 502 over the current 162-game season) to qualify for the batting title.